Recently, a secondary battery (also referred to as a rechargeable battery) has been widely applied to various portable electrical and electronic devices, such as toys and handheld devices, and the energy storage requirements on the secondary battery are higher and higher. Due to advantages, such as high energy, high power discharge and being environmentally-friendly, a lithium ion secondary battery has been gradually applied in the aforementioned fields.
During normal operation, it is often necessary for the rechargeable battery to cooperate with an integrated circuit chip of the other function, so as to achieve a desired operational effect. In general, the rechargeable battery and the integrated circuit chip are packaged separately, and then used in combination through connection of a circuit board and a conducting wire. As a result, peripheral elements and production processes are large in number, the cost is high, and the rechargeable battery and the integrated circuit chip have large volume and poor performance, which is contrary to the miniaturization and microminiaturization.
When the lithium ion secondary battery is packaged, the space occupied by each part of the lithium ion secondary battery is relatively fixed, and particularly, the polymer battery cell includes a positive electrode tab, a separator and the negative electrode tab inside thereof, a battery cell top seal with a specified height is provided at one end of the positive electrode tab facing away from the separator, for packaging. Since the battery cell top seal occupies a certain height of the polymer battery cell, available space of the polymer battery cell thus can be reduced. The space utilization of the polymer battery cell has much to do with the energy density and capacity of the lithium ion secondary battery, generally speaking, the larger is the space utilization of the polymer battery cell, the larger are the energy density and capacity of the lithium ion secondary battery. Therefore, the existing lithium ion secondary battery generally has problems that the energy density and capacity of the lithium ion secondary battery are low caused by low space utilization of the polymer battery cell.